How much does a new boiler cost?

Checked November 2026

Somewhere between £1,400 and £7,000 fitted, according to Which?. The government’s own figure for a typical gas boiler is about £3,500 including VAT. That’s a sensible number to keep in your head.

So why the huge gap? Mostly it’s the type of boiler and where it’s going. Then there’s whatever else the system needs while we’re there, and on some jobs that ends up being the bigger part of the bill.

We’re a small heating firm covering Hinckley, Coventry and Leamington Spa. We fit gas boilers and heat pumps. Below you’ll find what pushes the price up, what a decent quote looks like line by line, and our honest take on when a boiler isn’t the right call at all.

Does the type of boiler change the cost?

Yes. More than anything else. What’s on your wall now and what you want in its place sets the starting point.

The £1,400 to £7,000 range is from the Which? boiler cost guide (updated September 2025, though its price table dates from June 2024). Which? also tells people to get at least three quotes. We’d say the same. The £3,500 figure comes from the Department for Energy Security and Net Zero, in its 2026 business case for the Boiler Upgrade Scheme.

Neither of those is your quote, mind. Use them as a sense check. Someone quotes £1,200 for a straight swap? Ask why. Same goes for £8,000.

Not sure what you’ve got? Our guide to combi, system and regular boilers explains each one.

What affects the cost of a combi boiler?

Combi off the wall, new combi on. That’s normally the cheapest job going. No tank. No cylinder. Often no new pipework past the connections either.

On a combi the price mostly moves with the boiler itself, so the brand, the model and the size, plus the extras further down this page. One more thing. By law in England a combi needs an extra efficiency measure on top of the basics, which we cover under controls.

What affects the cost of a system or regular boiler?

Both run with a hot water cylinder. A regular boiler has tanks up in the loft as well. Swap like for like with a cylinder that’s still sound and honestly the job isn’t much bigger than a combi.

It gets dearer when the cylinder has had it, or when you’re going from a combi to a system with stored hot water. Which? puts a vented cylinder at £350 to £750 and an unvented one at £900 to £1,400 depending on size. On top of the boiler, that is.

What adds to the cost of a boiler replacement?

This is where cheap quotes and dear quotes part ways. The extras below are the ones we actually see come up on jobs.

How much does switching to a combi cost?

The cylinder comes out. So do the loft tanks. Then it all gets re-piped, and Which? says that adds £400 to £800 for labour and pipework.

You get the airing cupboard back, and the loft. Does a combi actually suit your house though? Separate question. With two bathrooms in regular use, or a heat pump on the cards, it might not. The types of boiler guide goes through that before you spend money switching.

Does moving the boiler cost more?

Yes. Leave it where it is and you keep the cost down. Move it and you’re paying for new gas and water pipes, a new route for the condensate and a new spot for the flue. The further it goes the more it costs. Shuffling a boiler along the same kitchen wall is one thing. Taking it from the kitchen up into the loft, or out to the garage, is a proper job.

A bigger boiler or a new location can also mean the gas pipe needs upgrading. Which? puts that at £100 to £400.

Will the system need flushing?

You don’t put a new boiler on dirty water. So the system gets cleaned and an inhibitor goes in, then a filter is fitted to catch whatever the clean leaves behind. Some systems need a full power flush, which Which? puts at £300 to £750 for a five-radiator system. Plenty don’t. Which? Trusted Traders says a simpler flush with clean mains water is sometimes all a system needs.

What controls does a new boiler need?

In England every new gas boiler needs a timer and a room thermostat. A combi needs one more measure on top under the Boiler Plus rules. That can be weather compensation or load compensation. Flue gas heat recovery counts too. So does a smart thermostat with automation and optimisation. Lots of modern controls tick that box without adding much to the price.

Fancy a smart thermostat anyway? Which? puts one at £100 to £250.

What should a boiler quote include?

Everything you’re paying for. A single number with “supply and fit new boiler” written next to it tells you almost nothing, so ask for the breakdown. On any gas boiler quote we’d expect to see:

• The boiler. Make, model and output in kW.
• The flue. Standard or extended, and where it comes out.
• System clean. Which method, and whether it’s a chemical flush or a power flush.
• Inhibitor and filter. Which filter, and where it goes.
• Controls. What’s being fitted, and how it meets the Boiler Plus rules on a combi.
• Pipework. Any changes to the gas, water or condensate pipes.
• Taking the old boiler away and disposing of it.
• Labour, commissioning and Building Regulations notification.
• The guarantee, and what you have to do to keep it.

Got your three quotes? Lay them out side by side and go down that list. Strike through anything one quote has and another hasn’t. More often than not the gap in price turns out to be a gap in what’s included. One has a power flush, the other a basic clean. One lists a smart thermostat and the other’s a plain dial.

Then look at the boilers. Two quotes for the same size combi can be for very different models with very different guarantees. Ask each installer why they picked that one for your house. A good installer gives you a reason about your home. Not about what happened to be in the van. Our guide on what size boiler you need explains how the output gets worked out.

Is the cheapest online boiler price really the cheapest?

Not always. The fixed price sites look tidy enough. A picture of a boiler and one number. Some are decent value, to be fair to them. The catch is you often can’t see what’s in the price until the fitter’s stood in your hallway.

So check before you compare. Does it cover the clean and the filter? The controls? A flue extension, gas pipe work or moving the condensate? If any of that gets added on the day, the cheap price stops being cheap.

And a website can’t look at your house. We’d rather come round, check the water and the pipework, and quote for your new boiler installation once and properly. Ask who’s actually fitting it too. When there’s a problem with the guarantee in five years you want a firm that still answers the phone.

Last thing. Make sure the paperwork’s in the price. A new boiler has to be notified under Building Regulations and the installer sorts that for you. GOV.UK says your certificate of compliance should then arrive within 30 days. Hasn’t turned up? Contact the scheme your installer is registered with. Keep the certificate safe. You’ll want it if you ever sell, and the guarantee registration belongs in the same drawer.

Are there grants for a new boiler?

No. Not for a gas boiler. The Boiler Upgrade Scheme gives £7,500 off an air source or ground source heat pump but boilers aren’t covered. The government set that out in its Warm Homes Plan, published in January 2026.

So if your boiler’s on its last legs and a heat pump has crossed your mind, look at both before you decide. We fit both. We genuinely don’t mind which you go for. Our guide on heat pump or gas boiler goes through it honestly.

Frequently asked questions

Is it cheaper to replace a combi with a combi?

Usually. Same type, same spot on the wall, and it’s about as simple as boiler jobs get. No cylinder to deal with and little or no new pipework. The price still moves with the boiler you pick and what the system needs, like a clean, a filter and controls that meet the Boiler Plus rules.

Is a new boiler worth it?

Depends on the one you’ve got. Working, safe and parts still available? No rush. But when it packs up every winter and each repair bill’s bigger than the last, a new one often makes more sense than nursing it along. Our guide to the signs you need a new boiler covers what to look for. We won’t promise you a figure on bills. Every home’s different. What we will do is look at your system and tell you straight whether to replace it now or leave it a while.

Want a proper price for your home? We’ll come out, have a look at the system and give you a quote that lists everything.

Sources

• Which?, “Boiler prices: how much does a new boiler cost?”, updated 17 September 2025 (price table June 2024), checked 3 November 2026, www.which.co.uk
• Department for Energy Security and Net Zero, “Boiler Upgrade Scheme 2026 to 2030: Summary Business Case” (footnote 8, gas boiler about £3,500 including VAT), checked 3 November 2026, assets.publishing.service.gov.uk
• GOV.UK, “Warm Homes Plan”, January 2026, checked 2 November 2026, www.gov.uk
• GOV.UK, “Building work, replacements and repairs to your home”, checked 3 November 2026, assets.publishing.service.gov.uk
• Which? Trusted Traders, “Quick guide to central heating power flushing”, checked 3 November 2026, trustedtraders.which.co.uk
• BEIS, “Boiler Plus: New standards for domestic boiler installations from April 2018” (FAQs), checked 3 November 2026, assets.publishing.service.gov.uk
• GOV.UK, “Approved Document L, Volume 1: Dwellings, 2021 edition incorporating 2023 amendments” (Table 6.2 and paragraph 6.2), checked 3 November 2026, assets.publishing.service.gov.uk